Low creatinine and elevated bun/creatinine ratio. Please explain?

Decrease in flow. Bun=blood urea nitrogen, byproduct of proteins ingested, if rise to high levels due to kidney problem, can cause toxic affects on the body. Creatinine= measurement of renal function. Normal bun/cr ratio about 10. The higher that ratio, the more likely it is not intrinsic kidney disease per se, but reduction in blood flow or volume to kidney, like when on strong diuretic-prerenal-reversible.